Stop in for a cup of coffee
For mechanical parts I usually let the parts guys look em upo and order the stuff (if they could).
Back then, parts store parts and rebuilt stuff ewas usually decent. Remember rebuilt distributors for $20 $25 ?
But for trim and weatherseals I needed the part numbers to ask the specialty dealers and look through Hemmings.
One exception being the K-H hubs and discs. When those went unobtainium, I was going through hemmings for those as well.
That's how I got tangled up with Mitchell's.